The presently described technology relates to a low-nickel austenitic stainless steel and method for producing same. More particularly, this invention relates to an austenitic stainless steel retaining excellent mechanical properties and corrosion resistance with low-nickel level, and method for producing the same.
In recent years, the commercially available stainless steels are mainly 300 series and 200 series between which there is a difference in the level of element nickel that results in an obvious difference in their properties and cost.
The 300 series is known as chromium-nickel stainless steel, of which the typical steel grade is 304 stainless steel characterized by the basic composition of 18Cr-8Ni. The 200 series is known as chromium-manganese stainless steel, of which the typical steel grade is 201 stainless steel characterized by the basic composition of 17Cr-5Ni-7Mn. The 200 series is also known as nickel-saving stainless steel, in which a part of nickel is replaced by manganese. Although the 200 series is low-priced, they have decreased corrosion resistance, improved tensile strength and elevated cold work hardening rate as compared to the 300 series, which result in elevated cost of casting's cold working.
Nickel resource is so rare that it exists naturally only in about 15 countries in the world. It is, therefore, necessary to develop an austenitic stainless steel having sufficient properties and decreased nickel content, so as to save nickel, reduce casting production cost and improve commercial competitiveness.
For this reason, a low-nickel austenitic stainless steel STC204Cu based on chromium-manganese stainless steel 201 has been developed by the inventors and used in investment casting, in order to improve corrosion resistance and cold work formability of Alloy 201.